Eyeballer

Eyeballers reject the more structured approaches to analysis that break down the data into small units and, from the perspective of the eyeballers, destroy the wholeness and some of the meaningfulness of the data.

Source: wiktionary

In my opinion, it is pretty obvious to the eyeballer of a time series chart whether a market is in a trending regime or a range-trading regime and, as we shall see, how one takes advantage of these regimes can differ between methodology and time frames anyway.

Source: wiktionary

Now a master eyeballer, I could accurately transpose almost any food into the equivalent value of another.

Source: wiktionary

Normally I wouldn't just eyeball it like this, though a pond does allow and even encourage the eyeballer.

Source: wiktionary